If it was my house being threatened, I might consider getting an excavator or dozer to dig trenches and or push up berms to divert the lava. Or do local rules prevent the private re-routing of lava. Seems sensible that they would. Just like I’m not allowed to do something with stormwater that would flood my neighbours’ properties.

it’s a mix of issues- lava flows are notoriously unpredictable (short of vaguely calculating the most direct descent, as they do over on the Hawai’i Volcano Observatory’s update page: http://hvo.wr.usgs.gov/maps/) so there’s no guarantee that barricading the homes wouldn’t further screw things up, let alone be entirely successful. Along with that, you also have cultural sensitivities around what the flow represents- diverting the flow could be seen as pretty blasphemous. There’s a pretty cool town hall video of locals opinions on diversion over here: http://www.bigislandvideonews.com/2014/09/05/video-hawaiians-rebuke-lava-diversion-talk/

Fair enough. It is a common argument, though, and worth addressing even if it wasn’t your argument.

There was a political cartoon I saw a decade or more ago that was a rotating newsreel of Americans saying “Sure, my house got wiped out by [tornado/mudslide/earthquake/flood/wildfire], but at least I’m not risking [next thing on the list] like those idiots in [place]!” Wish I could find it now.

Yes, good book. It also has a lot of detail on the difficulties of keeping New Orleans from flooding. It was published years before Katrina.

It’s fun to talk about the technical challenges of diverting lava and all, but in many of these cases, whether they be town built below sea level, mansions built on constantly eroding cliffs in Malibu, or a few homes built in the way of a lava flow, it makes a lot more economic sense to just write it off and relocate/rebuild the structures, rather than wage an all-out battle against powerful natural forces.